Charge for materials, equipment, and labor. Find out what your costs are for each and charge accordingly. If your not covering your costs plus some for each of those items, you're going the wrong direction/going out of business. You want to make a profit on each line listed above. Equipment includes trucks, tillers, etc. Charge for those items. For instance, if you needed and didn't own a tiller, you'd have to go rent one. If you do own one, charge for it. Equipment can be an overlooked line item on an estimate and those items can be significant money makers. As also mentioned, you want to have a contingency to replace/repair equipment if/when it does break.